Machine for casting heat radiating fins on preformed tubes



April 14, 1959 2,881,487

. J. J. CERK MACHINE FOR CASTING HEAT RADIATING FINS ON PREFORMED TUBES Filed March 10. 1954 5 Sheets-Sheet 1 i 7 I g INVENTOR JOHN J. CERK ATTORNEYS April 14, 1959 v CERK MACHINE FOR CASTING HEAT RADIATING FINS ON PREFORMED TUBES Filed, March 10. 1954 5 Sheets-Sheet 2 INVENTOR \JOHN J CLERK ATTORNEYS April 14, 1959 J J. CERK' 2,381,487

MACHINE FOR CASTING HEAT RADIATING FINS ON PREFORMED TUBES Filed March 10. 1954 5 Sheefs-Sheet s INVENTOR JOHN J.CERK

BY l zzg ATTORNEYS April 14, 1959 J. J. CERK 288L MACHINE FOR CASTING HEAT RADIATING FINS ON PREFORMED TUBES Filed March 10. 1954 5 Sheets-Sheet 5 I /9 /9 4 37 $0 5 W -W H jib! 60 4+ 4 55 2o /5 INVENTOR JOHN J.CERK

'- ATTORNEYS MACHINE FOR CASTING HEAT RADIATEIG FINS N PREFORIVIED TUBES John J. Cerlr, Milwaukee, Wis. Application March 10, 1954, Serial No. 415,276 3 Claims. (Cl. 22-58) This invention appertains to heat exchange units and more particularly to radiators or like elements of the type embodying spaced tubes around which air is forced for the exchange of heat from the tubes to the air or vice versa.

In automobile radiators and industrial heating units, the tubes are formed from metal and have secured thereto heat radiating fins. The connection of the fins to the tubes is a difficult problem, and to my knowledge two general methods are now utilized, namely, (1), the securing of individual fins in the nature of annular discs by soldering or the like and (2), by winding a strip spirally around the tubes and soldering or welding the inner edge of the strip to its tube. Both methods are costly, time consuming and require skill and accurate spacing of the fins is not always obtained, and as the fins are made from thin metal, the bending and contacting of individual fins usually takes place, lessening the etficiency of the radiator.

One of the primary objects of my invention is to provide a novel method and means for casting the fins directly on the tubes in an accurate spaced relation, and in such a manner that a plurality of tubes can be simultaneously handled and whereby as the fins are cast the tubes can be advanced to permit the continuous casting of fins on adjacent lengths of tubes, so that any desired length of tubes with fins thereon can be economically had.

Another salient object of my invention is to provide a novel means for casting heat radiating fins on tubes of any cross-sectional configuration and in such a manner that the fins will be braced longitudinally of the tubes to prevent bending and distortion of the fins and at the same time increase the radiation area of the tubes.

A further object of my invention is the provision of a casting machine having any desired number of pairs of mold blocks with a single injection means for molten metal for each pair of blocks, whereby to bring about the rapid and economical molding of fins on the tubes.

A further important object of my invention is the provision of spacer and mold plates for the mold blocks for receiving and supporting the tubes and for shaping the contour of the fins and brace ribs, the spacer and mold plates being freely removable whereby the plates as well as the mold blocks (when necessary) can be changed for molding fins of different characteristics.

Another further object of my invention is to provide novel means for carrying companion sections of the mold blocks and plates, whereby the sections of the mold blocks and plates can be readily separated to permit the advance of the tubes with the formed fins thereon in the machine.

A still further object of my invention is to provide means for cooling the machine and molten metal upon the injection of the molten metal'in the mold blocks, the cooling means including tubes extending longitudinally of the mold blocks and forming in conjunction with the mold blocks means for centering and holding the spacer and mold plates.

A still further important object of my invention is the provision of means for automatically trimming off the vent and sprue splash, as the tubes with the fins cast thereon are advanced in the machine.

A still further important object of my invention is the provision of a novel method of forming heat radiating Sttes Patet tubes which consist in holding preformed tubes in a casting machine with spacer and mold plates accurately placed around the tubes, injecting molten metal around the tubes and spacer and mold plates, cooling the molten metal and then advancing the tubes for the additional casting of fins on adjacent lengths of the tubes.

With these and other objects in view, the invention consists in the novel construction, arrangement and formation of parts as will be hereinafter more specifically described and claimed and illustrated in the accompanying drawings, in which drawings,

Figure 1 is an end elevation of a machine embodying the principles of my invention, parts of the machine being shown broken away and in section to illustrate structural detail, the view also showing the tubes having fins cast thereon for a portion of their length with the tubes in an advanced position for the molding of fins on adjacent lengths of tubes.

Figure 2 is a vertical sectional view through the machine taken on the line 2-41 f Figure 1, looking in the direction of the arrows, showing the plurality of pairs of mold blocks, the machine being shown in its closed position with the molten metal injected and the injection plungers in their raised returned positions;

Figure 3 is a horizontal sectional view taken on the line 3-3 of Figure 1, looking in the direction of the arrows;

Figure 4 is a detail fragmentary vertical sectional view taken transversely through the machine on the line 4-4 of Figure 3, looking in the direction of the arrows, the view showing the novel arrangement of the mold blocks and the spacer and mold plates;

Figure 5 is a detail vertical sectional view taken at right angles to Figure 4 and on the line 5-5 of Figure 4, the view showing a pair of companion mold blocks;

Figure 6 is a detail perspective view of a fragment of a tube with the fins and brace ribs cast thereon;

Figure 7 is a view similar to Figure 5, but illustrating another form of mold block and spacer and mold plates for molding fins of a different shape and on tubes of a different shape than shown in Figures 1 to 6, inclusive, and

Figure 8 is a detail perspective view of a fragment of a length of tube with fins molded thereon of a type being formed with the mold blocks and spacer and mold plates shown in Figure 7.

Referring to the drawings in detail, wherein similar reference characters designate corresponding parts throughout the several views the letter M generally indicates, a machine embodying the principles of my invention and it is to be understood that I do not desire to limit myself to the exact construction and form of machine shown and that the drawings illustrate one complete example of my machine.

The machine M includes a base or bed 10 in the nature of a heavy plate disposed in a horizontal plane mounted upon frame members 11 which can be secured to a floor or other suitable support. Securely fastened to the corners or at other desired points of the bed plate 10 are upright column posts 12. These posts rigidly support and carry at their upper ends a top frame plate 13. Arranged between the bed plate 10 and the top frame plate 13 are upper and lower press plates 14 and 15. One of the press plates is movable relative to the other and in the present instance, I have shown the upper press plate 14 rigidly secured to the column post in spaced relation to the top frame plate 13. The lower press plate 15 is slidably mounted on the posts 12 for free movement toward and away from the top press plate 14.

Between the press plates 14 and 15 are arranged a plurality of pairs of mold blocks 16, and in the present instance I have shown three pairs of such blocks, and

it is to be understood that any number of pairs of mold blocks can be provided as may be required by a particular plant. The mold blocks 16 extend transversely of the machine and each pair of blocks includes upper and lower mold block sections 17 and 18. The upper block sections 17 are removably secured to the rigid top press plate 14 by machine screws 19 and the lower mold block sections 18 are removably fastened to the movable press plate 15 by machine screws 20. From the description so far, it can be seen that when the movable press plate 15 is carried away from the top press plate 14 that the lower mold sections 18 are carried therewith to bring about a separation of the mold block sections 17 and 18, for a purpose which will later appear. The adjacent faces of the mold block sections 17 and 18 are provided with longitudinally extending cavities 21 of a particular shape in cross-section for receiving a plurality of individual combined spacer and mold plates 22. These mold and spacer plates are arranged in facial abutting relation throughout the length of the cavities 21 and where tubes of round configuration in cross-section are being handled, these plates are of an annular form so that when the plates are placed together a continuous bore will be provided of a shape to snugly receive a tube. The meeting faces of the spacer and mold plates are provided with companion die cavities 23, which define the shape of the fins being cast on the tubes and the connecting brace and radiating ribs connecting the fins. Obviously, as will hereinafter later appear, spacer and mold blocks of different shapes and with different die cavities can be utilized for handling different crosssectional configurations of tubes and different characters of radiating fins and braces. The spacer and mold plates themselves are also formed in companion upper and lower half sections, and the upper sections are carried by the upper sections 17 of the mold blocks and the lower sections are carried by the lower sections 18 of the mold blocks. At this point, it is to be noted that the meeting faces of the upper and lower companion half sections of the spacer and mold plates have formed therein cavities 24 which define dies for the forming of the connecting and brace ribs for the fins, and certain of these cavities open out to the mold blocks for receiving molten metal as the metal is injected into the mold blocks. The meeting faces of the mold block sections themselves are provided with longitudinal mating runs 25 and connecting branch runs 26 which lead to the cavities 24 so that molten metal injected in the runs will be received between the spacer and mold plates and their sections. By referring particularly to Figure 3, it can be seen that the run 25 extends between the cavities of a pair of cavities of the mold blocks and that each run 25 of a pair of mold blocks has communicating therewith a vertical gate 27 for molten metal and these gates for the pairs of mold blocks will be hereinafter referred to.

The sections of the combined spacer and mold plates 22 can be removably held in their respective mold block sections in different manners, but as illustrated the mold block sections have longitudinally extending companion ribs 28 which extend into the mold block cavities and the outer faces of the spacer and mold block sections are provided with grooves 29 which receive these ribs and the spacer and mold plate sections can he slid into the mold block cavities from one end of these ribs. The ribs form means for centering the spacer and mold plates and to further aid in the centering and holding of these plates I provide longitudinally extending pipes 30 in the mold block sections and these pipes receive cooling fluid to maintain the machine in a cool condition and to facilitate the cooling of the molten metal after the injection thereof. It can be seen that the outer surface of the sections of the spacer mold plates can be grooved as at 31 for receiving portions of these cooling pipes. The outer ends of the pipes project beyond the ends of the pairs of mold blocks and the ends of the pipes can be connected to supply and exhaust flexible hoses 32 and 33. The cooling fluid can be supplied to the hoses 32 in any desired way, and the hoses 33 can lead back to a storage tank, if such should be preferred.

The tubes being handled are indicated in Figures 1 to 6, by the reference character T, and it is to be understood that these tubes are formed from any desired metal and in any desired manner and that prior to the entrance of the tubes T into the machine that the same have a smooth outer surface.

As heretofore stated, the lower press plate 15 is movable toward and away from the upper press plate 14 and any suitable means can be provided for raising and lowering the press plate with its mold block sections. As illustrated, the bed plate 10 has securely bolted thereto a cylinder 34 in which the ram 35 is mounted for reciprocatory movement. The ram carries an upwardly extending piston rod 36 which is securely bolted to the lower press plate 15. Fluid under pressure is supplied to and exhausted from the opposite ends of the cylinder 34 in any desired way, and in proper sequence, by any preferred type of control valve, not shown. Hence, by admitting fluid under pressure to the lower end of the cylinder and exhausting fluid from the upper end of the cylinder, the ram can be moved upwardly carrying the press plate 15 therewith. Upon supplying fluid under pressure to the upper end of the cylinder and exhausting fluid from the lower end of the cylinder, the ram and the press plate can be lowered.

Each gate 27 has communicating with its upper end an injection cylinder 37 and communicating with the upper end of each injection cylinder is a suitably insulated molten metal supply pipe 38 which leads from a pot or other molten metal reservoir (not shown). Slidably mounted in each injection cylinder 37 is an injection piston 39 and these pistons are forcibly raised and lowered in any desired manner, such as by the use of hydraulic or like rams 40.

Each of the rams 40 is of identical construction and each can include a cylinder 41 rigidly secured to the top frame plate 13 having reciprocally mounted therein a piston 42 carrying an injection piston 39. The opposite ends of each cylinder are provided with ports 43 for the admittance and exhausting of fluid under pressure in proper sequence. Thus when fluid under pressure is admitted to the upper ports the pistons 42 will be lowered for forcing molten metal under relatively high pressure (1500 pounds per square inch) into the mold blocks and between the mold plates and fluid will be exhausted from the lower ends of the cylinders. When fluid under pressure is admitted to the lower ends of the cylinders, the injection pistons will be raised and fluid will be exhausted from the upper ends of the cylinder.

All of the cylinders are connected to common supply and exhaust pipes and these pipes are controlled by suitable valves (not shown). When the injection pistons or plungers 39 are in their extreme raised position, the lower ends thereof are just above the molten metal supply pipes 38 and in actual practice, just before the lowering of the injection pistons or plungers a gate or like valve can be opened from the pot or other molten metal reservoir to permit the flow of the metal into the injection cylinders 37.

Each gate is normally closed by a cylindrical slide valve 44 and all of these valves are held in their raised closed position by coil springs 45. When the injection cylinders 37 receive a charge of molten metal and the injection pistons 39 are forcibly lowered, the molten metal at a predetermined pressure will open the slide valves 44 against the springs 45 and the molten metal will then be forcibly injected into the mold blocks and between the mold plates.

After the discharge of the molten metal from the injection cylinders, and the flow of molten metal has been cut off from the pot, the injection pistons or plungers are raised bythe rams 41. Upon the cooling of the metal,

the lower press plate is lowered which will separate the mold block sections 17 and 18 and the mold plate sections. The tubes T with fins 46 cast thereon can be bodily lifted from the lower mold block and plate sections; at which time the tubes with the cast fins can be moved forwardly to place adjacent lengths of the tubes T in the mold cavities. The lower press plate 15 can now be raised and the above described molding cycle can again take place.

At this time, attention is called to the fact that end die plates 47 of substantially the same character as the die and spacer plates 22 are provided for preventing the running out of the molten metal from the ends of the mold blocks during the injection of the molten metal.

Obviously, adjacent tubes T in pairs of mold blocks will be joined by sprue and run splash and I have provided means forming a part of the machine M for trimming this run and sprue splash. As best shown in Figures 1 and 3, the top frame plate 13 and the top press plate 14 carry, by means of brackets 48, a set of gang saws 49. The shaft 50 for the gang saws is rotatably mounted in suitable bearings carried by the brackets and this shaft 50 may be directly driven from an electric motor 51. The set of gang saws is arranged in pairs, and the saws 52 of each pair are spaced a predetermined distance apart for engaging the opposite sides of the tubes T with the formed fins 46 thereon.

When the fins are cast and the tubes T are raised from the lowered sections of the mold blocks, the tubes are shoved forwardly and are fed between the saws 52. Upon the trimming of the formed fins on the tubes, all of the fins will be connected by brace ribs 53, as best shown in Figure 6. In the form of tube shown in Figure 6 equidistantly spaced annular fins 46 are formed connected by the ribs 53 which project radially from the opposite sides of the tubes T.

As heretofore brought out various cross-sectional configurations of tubes can be handled and various types of fins can be cast thereon, and in Figure 8, I have shown another form of radiator tube and fin and in Figure 7 mold blocks 54 and spacer plates 55 for forming this particular type of fin.

Referring to Figure 8, it can be seen that a fiat tube 56 is provided and cast on the opposite sides of the tube are outwardly projecting tapered fins 57. All of the fins are connected by longitudinally extending ribs 58 which project from the opposite sides of the narrow walls of the tubes 56. The fins 57 themselves have formed thereon during the casting thereof strengthening brace webs 59. The fins on one side have these ribs on their upper faces and the fins on the other side have the webs on their lower faces. The purpose of this is to permit the placing of tubes in a radiator in close proximity with the fins of one tube extending between the fins of an. adjacent tube.

Now referring to Figure 7, the mold blocks 54 and the spacer and mold or die plates 55 are shaped to correspond to the configuration of the tube 56 and to cast the fins 57 and ribs 58 thereon. In this particular form, coding tubes 60 of a square shape in cross section extend through the mold blocks 54 and engage the spacer and mold or die plates 55 to hold these plates in proper position.

It is again stressed that various types of mold blocks and spacer and mold plates can be utilized to accommodate the diiferent characters of tubes and to cast fins there on of different shapes.

From the foregoing description, have provided a machine and method for producing a unicast radiator tube and fin structure. By my machine and method, not only are radiator tubes with fins thereon economically made but a durable and strong radiator tube structure is provided.

Changes in details may be made without departing from the spirit or the scope of this invention, but what I claim as new is:

it can be seen that I l. A machine for casting equidistantly spaced heat radiating fins on pre-formed tubes comprising separable press plates, mold blocks including companion half sec tions, means securing the companion half sections to the press plates, combined spacer and mold plates formed in companion half sections carried by the mold blocks and separable with the sections of the mold blocks and press plates, said combined spacer and mold plates being arranged in facial abutting relation with the meeting faces provided with die cavities of a shape to correspond to the configuration of a desired heat radiating fin, the meeting edges of the companion half sections of the combined spacer and mold plates having longitudinally aligned seats, a preformed tube fitted on the seats, the die cavities opening into said seats and said meeting edges also having cavities communicating with the first named cavities, the meeting faces of the mold block sections having runs for molten metal communicating with the last named cavities, said mold blocks having gates communicating with the runs, injection cylinders communicating with the gates, means for supplying molten metal to the cylinders, injection pistons slidable in the cylinders, and means for forcibly actuating the pistons.

2. A machine for casting equidistantly spaced heat radiating fins on pre-formed tubes as defined in claim 1, the tubes with fins cast thereon being bodily movable upon the separation of the press plates and shiftable longitudinally of the mold blocks to permit the placing of adjacent smooth lengths of tubes in the machine for the casting of the fins thereon.

3. A machine for casting equidistantly spaced heat radiating fins on preformed tubes comprising press plates at least one of which is movable toward the other, companion mold block sections carried by the meeting faces of the press plates, combined spacer and mold plates carried by the mold block sections arranged in facial relation and having their meeting faces provided with die cavities corresponding to the shape of fins to be cast on the tube, and said combined spacer and mold blocks having longitudinally aligned bores, a preformed tube snugly fitted in the longitudinally aligned bores and extending the length thereof, the die cavities in the meeting faces of the combined spacer and mold blocks communicating with the bores, the mold block sections having runs communicating with the cavities, and means for forcing molten metal under pressure into the cavities.

References Cited in the file of this patent UNITED STATES PATENTS 421,900 Bouton Feb. 25, 1890 1,083,198 Debbas Dec. 30, 1913 1,717,254 Polak June 11, 1929 1,769,456 Pickering July 1, 1930 1,880,786 Carey Oct. 4, 1932 1,975,889 Whiteley Oct. 9, 1934 1,975,966 Morin Oct. 9, 1934 2,137,764 Wagner Nov. 22, 1938 2,161,898 Ledbetter June 13, 1939 2,201,024 Brown May 14, 1940 2,206,211 Wagner July 2, 1940 2,319,479 Ryder May 18, 1943 2,332,856 Kalajian Oct. 26, 1943 2,499,292 Black Feb. 28, 1950 2,502,767 Venner et al. Apr. 4, 1950 2,516,373 Ehlert et al. July 25, 1950 2,529,348 Mustee Nov. 7, 1950 2,569,083 Wilhelm Sept. 25, 1951 2,600,559 McCauley June 17, 1952 2,620,171 Dubin et a1. Dec. 2, 1952 2,704,388 West Mar. 22, 1955 2,704,959 Morin et al. June 18, 1955 FOREIGN PATENTS 145,451 Australia Feb. 27, 1952 

